1. Field of the Invention
The present invention relates to expandable tubing and methods of sealing a connection between expandable tubulars. In particular, but not exclusively, the present invention relates to methods of sealing a connection between expandable tubulars post-expansion.
2. Description of the Related Art
In the oil and gas exploration and production industry, there has been much research into the development of expandable tubulars in recent years. A number of different types of expandable tubing have been developed, including expandable sand-exclusion tubing based assemblies and solid expandable tubing such as expandable casing, liner, patches and straddles.
The tubing is typically expanded using either an expansion cone or mandrel, or a roller expansion tool, such as that disclosed in the applicant's International patent publication no. WO 00/37766.
In certain circumstances, it is necessary to seal connections between lengths of expandable tubing, such as between sections of tubing forming a casing or liner string. However, it has been found difficult to obtain an adequate seal between the tubing sections post-expansion.
One reason for this is that a relative radial separation can occur between male and female (pin and box) connections by which adjacent tubing sections are coupled together, following expansion.
It is amongst the objects of embodiments of the present invention to obviate or mitigate the foregoing disadvantage.